A magnetic resonance imaging (MRI) apparatus is an apparatus which acquires chemical and physical micro-information of a substance utilizing a phenomenon whereby a target nuclear spin population, when placed in a magnetic field, resonates with a high-frequency magnetic field rotating at a specific frequency (resonant frequency) in accordance with the intrinsic magnetic moment and existing magnetic field intensity of the magnetic field, and generates a signal (a nuclear magnetic resonance (NMR) signal) in a nuclear spin relaxation process.
Such an MRI apparatus can acquire images of regions of the whole body, such as the head and neck, the abdomen and the spine. For this reason, it is often the case that the images acquired by the MRI apparatus are utilized for the purpose of diagnosis. Also, in recent years, MRI apparatus has been used to examine breasts too. It is reported that breast images acquired by MRI apparatus are particularly effective in early detection of breast cancer, diagnosing whether a lesion is benign or malignant, and diagnosing spread of a tumor.
However, with common image diagnosis of mammary gland disease, examination by X-ray mammography is typically first selected for reasons of diagnostic evidence, prevalence of such apparatus, and ease of examination. As a secondary choice, an examination by ultrasound diagnostic apparatus may typically also be made. It is also now often the case that an MRI examination is complementarily utilized—when determining whether or not a tumor mass has spread, with reference to an earlier image diagnosis by X-ray mammography or ultrasound.